Abarth

What’s good compression results if I just use a normal compression tester?

I did a compression test on one of those auto FD rx7s on trademe, had 100k on the clock and doesn’t look rebuilt 

Heated up the engine then I removed the bottom plugs in both rotors, left the top ones in. Hooked up a jumpstart battery pack so the car had good voltage. WOT cranked key and holding the pressure valve down I got 3 even pulses but only at 75psi for both rotors.

Seems way too low but it started both cold and hot easy as. A lot of white smoke on start up tho.

i know compression depends on cranking speed a lot but with a good battery cranking speed should be reasonably high like 200rpm giving a higher compression result right? 

What’s the cost of the rim and shipping to get them over here?

they look mint and alloys a nice upgrade.

does hole angle matter as they are lacing up to drum hubs?

Yeah, CWC wheels in the U.K. do the Honda specific rims for around £100 / $190nzd depending on finish.

Looked at shipping too and the YouShop calculator reckons it’ll be round $66.

So $250ish landed is still cheaper than getting it here. 

I’m wanting to stick some slightly wider rims on the little Honda and relace them with new spokes.

Its currently got the factory WM1 on the front and WM2 on the back both 36 hole. 

Wanting to chuck the WM2 on the front and get a WM3 for the rear. Anyone know where to get an 18 inch steel WM3 18 hole rim from? Ideally keen to buy new in NZ.

Man thats sweet, love the factory colours on the tank. 

37 minutes ago, sheepers said:

i wondered who that was.

Yeah its been a while, last time we met was when I had Fiat Strada in the oldschool show n shine at the 4nRotary nationals. 

Thats a sweet clock, I really like to the steampunk kinda theme, suits nixies a lot I reckon. I was debating whether to get the side view tubes but the top view IN-12a's are so cheap.

https://www.pvelectronics.co.uk/index.php?main_page=product_info&cPath=1&products_id=140

I'm not a huge fan of LED's under the tubes either, mines currently set to 2 out of 9 in brightness settings just so there is a bit of orange but not taking away from the tubes neon glow. 

Next step for me is to build the case, thinking vintage/steampunk wood with brass buttons. 

Awesome nixie projects man!

Just completed this kit from PV Electronics over here in the UK. 

First clock build which was good fun, so much soldering but totally worth it as the neon glow from the nixie tube looks epic in real life. I'm hooked!

The tubes are IN-12a's which have a 18mm digit height.

Its also running orange led's behind the tubes, had the option to run a variety of colours but felt orange suits. 

Tidy Punto GT build

http://forum.wheel-whores.com/viewtopic.php?f=43&t=20879

It runs!!

Took it for a couple rides to bed the rings in and already it feels like a different machine! Rings must have already been broken before I brought it, probably the reason it was parked up in the first place. Anyways fixed now! Way more torque all round, so much better in traffic.

Got it back on the dyno to measure how many horses were added to the stables. Netted almost 22hp up from 15hp so super stoked with that!!!

Still needs a final tune, valve clearances, re balance carbs, check torque on headnuts etc. But stoked with 22hp.

Happy NY’s OS!!! 

Right o, after a quick visit back to NZ it was time to get stuck back into the Honda.

This is sitting at the workshop in a sad state.

While I was in NZ the machinist bored the cylinders to match the +1mm oversized pistons, skim the head, cut the valves and valve seats.

These Honda motors run a reasonably tight piston to wall clearance of 0.0014 thou which all checked out when we measured the walls, pistons and gapped the rings. Ring gaps are meant to be between 0.015~0.035mm and they measured in at 0.025mm so bang on. 

Took ages to remove the old gaskets from the faces, even with this nifty air powered tool it still to a good hour of cleaning the surfaces.

Added in new timing chain, tensioner etc all Honda OEM stuff

Old cam chain tensioner vs new, apparently these tensioners have a bit of a bad rep of coming apart but this one seems to held up alright, yes the rubber wheels are a bit beaten up but 40 years of heat cycles I'm surprised it isn't more.

Got it all back together and torqued up, the build had been pretty much to factory spec so everything went back together easily enough. 

By this time it was almost midnight so now the motor is sitting in the frame waiting to be finished. Next update will hopefully had this motor running!! 

My Honda has same equally as bad charging system but after changing over to the new reg/rectifier and LEDs (brakes, dials, park light) I can drive round with the headlight on 100% of the time without the battery going flat. Definitely worth doing. 

Are you running the 35w headlight? Mine still does, its not great, thinking of switching to 55w but again back to power issues. 

Got the motor out, pulled it down, unsurprisingly the rings were broken.

What was surprising was how broken the rings were. Still good for 10k rpm on the dyno haha! There was also a huge amount of slop between the cylinder and piston.

Checked over the rest of the engine and everything else looks in good nic. Crank is perfect and the head looks good. So just a case of really worn pistons and rings. 

Cylinder and head are at the machinists now getting machined to accept the +1mm pistons.

In prep for the rebuild I got measuring some numbers.

The digital scales came out to measure the weight of the pistons, rings and pin. Amazingly they all were perfectly equal in weight to the nearest gram, stoked. 

Next piston to cylinder clearance; its only 0.0008 ~ 0.0019 inch as apparently these ART Honda pistons don't expand much. I'll keep these numbers for the machinist. 

Lastly these motors run a 9.5:1 compression ratio so there is a bit of room to remove a bit of meat from the head/cylinders. Been reading online guys removing up to 0.02 inch before running into clearance issues, this also increases compression to around 10.3:1ish. Nice to know as I'm 99% sure the head isn't flat anymore.

Strapped this onto the dyno and did a couple of runs to see what power its making pre engine rebuild. 

Only made 15HP and puked a huge puddle of oil from breather pipe at about 10k rpms, far cry from the factory 25 - 30HP. Power delivery is nice and linear with the air/fuel mixtures being spot on, so happy about that.

After this we checked compression which was 80psi on the left and 170psi on the right.

Also did a leak down test with 40% loss on the left, which again meant oil spewing out the oil breather and making a huge mess. 

Good basis to start the engine rebuild, we'll get it back on the dyno again after the rebuild. If it does make 25 HP after the freshen up then its going to feel like a rocket ship compared to how it had been running.

Just waiting on some cam tensioner parts to arrive then next weekend we'll start pulling this engine down and sending bits off to get machined. Exciting.

Added new low rise handle bars, hid all the wiring inside and vintage styled grips. 

The engine has been suffering from a bit of blowby, white smoke blowing out the crank case breather and generally been down on power. 

So rebuild time! +1mm oversized pistons to add a little bit more displacement, I think it adds something like 9cc lol. I'll dyno it before and after to see what extra HPs have its making after the freshen up. 

Got a few other bits and piece to add while I have it apart like cam chain tensioner, cam chain, some new chrome pieces.

Looking forward to the rebuild!!

You can still get the filters brand new from David Silver spares in the US then YouShop it home.

https://www.davidsilverspares.com/parts/by-part-number/partnumber_5985/

$45 usd each still ain’t cheap but I usually order a tone of other small stuff like replacing rusted out bolts and stuff too

All the part numbers are listed here:

https://www.cmsnl.com/honda-cb175k7-super-sport-1973-usa_model423/partslist/?model_q=cb175

I just put the part numbers in the David silver site and build up a decent shopping basket. Easy to spend way too much lol. 

Upgraded the Puntos fuel system to a Walbro 255lt pump. It's the standard in tank pump which replaces the factory Bosch one.

Everything is sweet but shit is it noisy. Was thinking is there a smaller capacity pump? 

The Punto is now making round 250hp so I would only need to run something like an Evo or Silvia fuel pump? Does anyone know if all these fuel pumps are the same size? 

True, I'm sure Bill used to own this for a number of years as I talked to him like ten years ago and he mentioned the motors just been built but their is still the body to go. 

Anyways looks like the car is being well looked after now. Looking forward to the updates 

Sweet Spitfire @Rob2180 , looks familiar did the car come from Hawkesbay?

Same as over here in the U.K., you can get a RX8 with about 100 tho km for £1,000. 

Amazingly cheap. 

9 minutes ago, Evan said:

Re: mechanical stripping. Go to Supercheap auto and buy on of these:

http://www.supercheapauto.co.nz/Product/Rockwell-ShopSeries-Car-Polisher-180mm-1200-Watt/135285?menuFrom=1021759

You want one of those because A. it's $100 and therefore it's disposable and B. it has variable speed control.

I have one of these, they are really good.

I've thrashed it and its still running like a champ. Mostly for cutting and polishing the paint though.